Snap-action electrical switch

ABSTRACT

1,132,863. Retractive switches. ALEX NEHER AG. METALLWAREN &amp; WERKZEUGFABRIK. 10 Nov., 1965 [25 Nov., 1964], No. 47650/65. Heading H1N. A snap-action switch comprises a contact blade 3 connected to one end of a leaf spring 9 having a bowed portion joined to a straight portion forming a chord to the bowed portion. A lever 10 acted on by a push-button 8 is connected to the other end of the spring 9. Modifications are described in which the lever presses on the chord, the said other end of spring 9 being connected to a fixed point, and the button may be connected to the lever on a second spring of similar form. The first and second springs may be formed of two parts hinged together.

March 21, 1967 G. KITTEL 3,310,644

7 Y SNAP-ACTION ELECTRICAL SWITCH Filed Nov. 22, 1965 2 Sheets-Sheet lMarch 21, 1967 G. KlTTEL SNAP-ACTION ELECTRICAL SWITCH 2 Sheets-Sheet 2Filed Nov. 22, 1965 United States Patent M 3,310,644 SNAP-ACTIONELECTRICAL SWITCH Gunther Kittel, Ebnat-Kappel, Switzerland, assignor toAlex Neher AG Metallwaren & Werkzeugfabrik, Ebnat-Kappel, Switzerland, aSwiss firm Filed Nov. 22, 1965, Ser. No. 508,939 3 Claims. (Cl. 200-67)This invention relates to an electrical switch which comprises fixedcontact parts, and movable contact means which are arranged on a metalblade, this blade being movable by a loaded spring, when the switch isoperated, to bring its contact means into impacting engagement with oneof the fixed contact parts.

It is an object of the invention to provide a switch of this type withan improved spring action for the purpose stated.

To this end, in the switch according to the invention the spring, whichcomprises a leaf spring, has a part of bowed curvature and a part whichfollows a chord of this curve, and one end of this spring is connectedto the free end of the movable metal blade, whilst the other end of thespring is connected either to a lever or to a fixed part, whilst a pressbutton for operating the switch, for the purpose of actuating thespring, engages the latter or directly engages the movable metal blade,through a lever arm which is mounted for free pivotal movement in theswitch.

The invention is illustrated by way of example in the accompanyingdrawings in which:

FIGURES 1 to 6 illustrate six embodiments of the switch in side view,with the side wall of the switch housing removed, and

FIGURES 7 and 8 are respectively a side view and a plan view of amodified form of spring which can be used in the embodiments illustratedin FIGURES 1 to 6.

In all the embodiments of switch illustrated in FIG- URES 1 to 6, use ismade of a housing 1 of electricallyinsulating material. Metal plates 2are embedded in the material of this housing, and one end thereofprojects from the housing to provide for connections to electricalequipment with which the switch is used. A metal blade 3 is inserted inthe central plate, and the part thereof projecting into a recess 4 inthe housing has contacts 5 for cooperation with the two outer plates 2.

In addition to the recess 4, the housing 1 is formed with a bore 6 whichopens into this recess, and with a number of slotted recesses 7 whichextend outwards from the recess 4 and have their ends cocked off at anangle. In addition a press button 8 is displace-ably mounted in the wallof the housing 1.

In the embodiment illustrated in FIGURE 1, one end of a leaf spring 9,which is composed of a part following a bowed curve, and another partdisposed as a chord to this curve, is connectedto the end of the blade3. Coupled to the other end of this spring 9, i.e. of the chord-formingpart of the latter, is a lever arm 10 which is held in a pin 11pivotable in the bore 6. An intermediate part of the lever arm 10 isdisposed beneath the press button 8.

The switch illustrated in FIGURE 2 differs from that of FIGURE 1 in thata holder 12 is inserted in one of the recesses 7 and is connected to thefree end of the chordforming part of the spring 9, and the end of thelever arm, in this case denoted 10a, bears against the chord-formingpart of the spring 9.

In the form of switch illustrated in FIGURE 3 a second spring 13, ofsimilar form to spring 9, is disposedbeneath the press button 8 and isarranged to transmit the motion of the latter to the lever arm (heredenoted 10b). The secondary spring 13 is of like form to spring 9, i.e.has a curved portion adjoined to a chord-forming portion,

3,310,644 Patented Mar. 21, 1967 and it is mounted in the housing by aholder 14 which engages the end of the chord-forming part of the spring.The opposite end of the spring 13 engages an upper part of the arm 10b,and it will be observed that this has a downwardly-extending section 10which is coupled at its lower end to the outer end of the chord-formingpart of spring 9.

The further embodiments of switch according to the invention andillustrated in FIGURES 4 to 6 all use this feature of a secondary spring13 of the nature illustrated in FIGURE 3.

Thus, in FIGURE 4 the end of the chord-forming part of the spring 9 isanchored by a holder 15' mounted in one of the slots 7 in the body ofthe housing in a similar fashion to the holder 12 of FIGURE 2. Thesection 10 of the lever arm (which is somewhat similar to that carryingthe same reference numeral in FIGURE 3) bears at its lower end against apoint on the chord-forming part of spring 9 away from the anchored endof this part. In this case the spring 13 is connected between the leverarm 10c and a holder 14, similarly to the arrangement of spring 13 inFIGURE 3.

In the arrangement illustrated in FIGURE 5 the spring 9 is mounted insimilar fashion to the arrangement depicted in FIGURES 2 and 4, that isto say it is connected at one end to the blade 3 and at the oppositeend, i.e. the ultimate end of the chord-forming part, is engaged by aholder 17, corresponding to the holders 12 and 15 previously described.The secondary spring 13 is in this case generally similar in form to thesecondary springs 13 in the embodiments previously described, but is, ineffect, reversed in relation to the press butt-on 8, the end of thestraight chord-forming part of spring 13 being disposed at theright-hand side of press button 8 and there being anchored to a holder18 engaged in the wall of the housing. The other end of this secondaryspring 13 is connected to the lever arm, here denoted 10d, and it willbe observed that the latter has a knee-forming portion which bearsslidingly against the chord-forming part of the main impact spring 9.

In the case of the switch illustrated in FIGURE 6, it will be observedthat the end of the chord-forming part of spring 9 is engaged by aholder 19, which projects inwards from the right-hand end wall of thehousing, whilst the opposite end of this spring, i.e. the free end ofthe curved portion, is connected to the blade 3. V

In this instance, moreover, the secondary spring 13 is mounted similarlyto the corresponding spring in the FIG- URE 3 construction, that is tosay the free end of the chord-forming part is engaged by a holder 20which is mounted in the slot 7 in the upper wall of the housing, whilstthe opposite end of the spring, i.e. the free end of the curved partthereof, is engaged with the upper portion of the lever arm (heredenoted 102). This lever 10e is formed with a downwardly extendingsection 10g which is provided with an opening which receives the blade3.

The form of spring 9 devised in accordance with this invention, has aspring characteristic providing for a relatively high stress build upwhen the button 8 is depressed, and this characteristic is furtheraugmented where use is made of the similar form of secondary spring 13.In use, the blade 3 will be flipped over abruptly as soon as thetransmission to the blade 3 is suflicient to flex this beyond the restposition of the blade. As a consequence of the nature .of spring 9, orsprings 9 and 13 where the secondary spring is employed, the blade 3will make or break the contacts very rapidly and cleanly, and any arcingwill be immediately extinguished.

Moreover, the form of the spring(s) devised in accordance with theinvention, and the resulting spring characteristics,fhave the effect ofincreasing the ratio between the pressure applied to the button 8, andthe pressure applied between the contacts.

Instead of being in one piece, as illustrated in FIG- URES 1 to 6, theleaf springs 9 and 13 may be made in two parts. This modification isillustrated in side view and plan view in FIGURES 7 and 8, here beingshown on a somewhat larger scale. As will be observed from thesefigures, in this modification the chord-forming part 21 of the spring isarticulated adjacent one end with the part 22 of the spring which is ofcurved form.

What I claim is:

1. In an electrical switch having a housing containing spaced apartfixed contacts and a metal contact blade movable in said housing betweensaid fixed contacts to selectively engage the latter; the combination ofan impact-controlling leaf spring having a curved section and a straightsection extending chordally in relation to said curved section to definefirst and second termini of said leaf spring at free ends of said curvedsection and said straight section, respectively, one of said termini ofthe leaf spring being articulately connected to said movable contactblade, and actuating means including a lever arm pivotally mounted insaid housing and articulately connected to the :other of said termini ofthe leaf spring to move said contact blade through said leaf spring inresponse to rocking of said lever arm and a press button mounted in saidhousing and operable from the exterior of the latter to rock said leverarm.

2. An electrical switch according to claim 1; wherein said press buttonbears directly :on said lever arm to eifect rocking of the latter.

3. An electrical switch according to claim 1; wherein said actuatingmeans further includes a second leaf spring of a form similar to that ofthe first mentioned leaf spring and having one of said termini of saidsecond leaf spring connected to said lever arm and said press buttonengaging said straight section of said second leaf spring so that thelatter forms a motion-transmitting means between said press button andsaid lever arm.

References Cited by the Examiner UNITED STATES PATENTS 2,487,374 11/1949Riche et al. 3,176,109 4/ 1965 Wodtke. 3,210,497 10/ 1965 Schwartz.

ROBERT K. SCHAEFER, Primary Examiner.

D. SMITH, Assistant Examiner.

1. IN AN ELECTRICAL SWITCH HAVING A HOUSING CONTAINING SPACED APARTFIXED CONTACTS AND A METAL CONTACT BLADE MOVABLE IN SAID HOUSING BETWEENSAID FIXED CONTACTS TO SELECTIVELY ENGAGE THE LATTER; THE COMBINATION OFAN IMPACT-CONTROLLING LEAF SPRING HAVING A CURVED SECTION AND A STRAIGHTSECTION EXTENDING CHORDALLY IN RELATION TO SAID CURVED SECTION TO DEFINEFIRST AND SECOND TERMINI OF SAID LEAF SPRING AT FREE ENDS OF SAID CURVEDSECTION AND SAID STRAIGHT SECTION, RESPECTIVELY, ONE OF SAID TERMINI OFTHE LEAF SPRING BEING ARTICULATELY CONNECTED TO SAID MOVABLE CONTACTBLADE, AND ACTUATING MEANS INCLYDING A LEVER ARM PIVOTALLY MOUNTED INSAID HOUSING AND ARTICULATELY CONNECTED TO THE OTHER OF SAID TERMINI OFTHE LEAF SPRING TO MOVE SAID CONTACT BLADE THROUGH SAID LEAF SPRING INRESPONSE TO ROCKING OF SAID LEVER ARM AND A PRESS BUTTON MOUNTED IN SAIDHOUSING AND OPERABLE FROM THE EXTERIOR OF THE LATTER TO ROCK SAID LEVERARM.